优化RingChart的渐变效果

CHANGELOG-EN.md

@@ -39,6 +39,7 @@
 
 ## master
 
+* (2021.08.31) Optimized the gradient effect of `RingChart`
 * (2021.08.31) Fixed bug where `SerieLabel` does not refresh when `DataZoom` is dragged (#165)
 * (2021.08.25) Fixed an issue where the theme switch could not be save to the scene (#166)
 * (2021.08.24) Added `Animation`'s `alongWithLinePath`

CHANGELOG.md

@@ -39,6 +39,7 @@
 
 ## master
 
+* (2021.08.31) 优化`RingChart`的渐变效果
 * (2021.08.31) 修复`DataZoom`拖动时`SerieLabel`不刷新的问题 (#165)
 * (2021.08.25) 修复`Theme`主题切换无法保持到场景上的问题 (#166)
 * (2021.08.24) 增加`Animation`的`alongWithLinePath`参数设置折线轨迹匀速动画

Runtime/Internal/DrawSerieRing.cs

@@ -104,6 +104,14 @@ namespace XCharts
                         itemStyle.backgroundColor, Color.clear, 0, 360, borderWidth, borderColor, 0,
                         chart.settings.cicleSmoothness, false, serie.clockwise);
                 }
+                var isGradient = !UGLHelper.IsValueEqualsColor(itemColor, itemToColor);
+                if (isGradient)
+                {
+                    if (serie.clockwise)
+                        itemToColor = Color.Lerp(itemColor, itemToColor, toDegree / (startDegree + 360));
+                    else
+                        itemToColor = Color.Lerp(itemToColor, itemColor, toDegree / (startDegree + 360));
+                }
                 UGL.DrawDoughnut(vh, serie.runtimeCenterPos, insideRadius, outsideRadius, itemColor, itemToColor,
                     Color.clear, startDegree, toDegree, borderWidth, borderColor, 0, chart.settings.cicleSmoothness,
                     roundCap, serie.clockwise);